This invention relates in general to power operated locks for door latch assemblies and in particular to an improved adjunct actuator structure for vehicle door locks.
Vehicles such as passenger cars are commonly equipped with individual latch assemblies which secure respective passenger and driver doors closed. Each latch assembly is typically provided with a manual latch actuating mechanism for unlatching the latch assembly from outside and inside the vehicle, for example, respective inner and outer door handles. Each latch assembly is also typically provided with an individual lock for preventing unauthorized opening of the vehicle door. These locks are typically operatively coupled to a key-operated mechanism for manually operating the lock from the exterior of the vehicle and provided with a manual mechanism for operating the lock from the interior of the vehicle, such as a respective sill button.
Furthermore these locks are commonly provided with a respective power actuator for operating the lock. Such actuators may be controlled by the actuation of a remote device such as an electrical switch located inside the vehicle or a hand held transmitter operatively coupled to the remote operating mechanism through a vehicle security system.
It has been a common practice to mount a vehicle door latch and the associated lock on a common frame to form a latch assembly, which is then fastened to the vehicle at the appropriate location. If power operation of the lock was to be provided for in certain models of a vehicle, a power lock actuator could be provided. If the power lock actuator is mounted on a separate actuator frame, which was then fastened to the vehicle at a location remote from the latch frame upon which the latch and lock were mounted, the power actuator is referred to as a remote lock actuator. The remote lock actuator was then operatively coupled to the lock by a rod or other linkage transmitting motion from the remote lock actuator to the lock. Such a connecting rod was often quite lengthy, relatively easy to damage during use or servicing of door components, and did not always permit optimum geometry in connecting to the lock on the latch assembly. Furthermore, such connecting rods are relatively vulnerable to manipulation by thieves reaching into the interior of vehicle doors with various tools, allowing the lock to be defeated.
More recently, power door locks have become a standard feature in some vehicles. This has lead to power lock actuators being designed which are mounted on the same frame as the latch and the associated lock. These are referred to as integrated door lock actuators. Integrated door lock actuators eliminate the lengthy connecting rod between the remote lock actuator and lock, but lack flexibility in application. Such an arrangement would be unsuitable for use in situations where a single design of latch assembly is to be used in a line of vehicles in which some models would have power lock actuation capability and some are to be strictly manually operated.
The power lock actuator should not interfere with manual operation of the lock when the power lock actuator is operatively connected to the lock mechanism of the latch assembly. It is known to provide lost motion in a power lock actuator so that when the lock mechanism of the latch assembly is manually operated, for example with a door lock key, not all of the movable components of the power lock actuator have to be manually back-driven. This lost motion feature reduces the operating effort required for manual operation of the lock mechanism. In order to provide this lost motion feature for a power actuator, the power actuators of the past have typically been provided with some sort of preloaded spring, which may be difficult to assemble during manufacture of the power actuator.